U.S. Believes Syria Used Gas

White House Shifts Assessment on Chemical Weapons; New Pressure to Respond

By

Adam Entous

Updated April 25, 2013 8:45 p.m. ET

ABU DHABI—U.S. intelligence agencies now believe the embattled regime of Syrian President Bashar al-Assad has used chemical weapons, the White House told Congress on Thursday, saying the agencies have "varying degrees of confidence" in the assessment.

Coming in a detailed letter to lawmakers, the findings mark a turning point in the Obama administration's approach to the two-year civil war, constituting the administration's...